Sidney h



(No Model.)

S. H. SHORT. AUTOMATIC GUT-OUT FOR DYNAMO ELECTRIC MACHINES. No. 458,666. Patented Sept. 1,1891,

3& 2 61mm;

UNITED STATES PATENT QFFICE.

SIDNEY H. SHORT, OF CLEVELAND, OHIO, ASSIGNOR TO THE SHORT ELEC- TRIO RAILlVAY COMPANY, OF SAME PLACE.

AUTOMATIC CUT-OUT FOR DYNAMO-ELECTRIC MACHINES.

SPECIFICATION forming part of Letters Patent No. 458,666, dated September 1, 1891.

Application filed October 29, 1889. Serial No. 328,544. (No model.)

To all whom it may concern; of the external or working circuit, which are Be it known that I, SIDNEY H. SHORT, of connected to the binding-posts a b. In the Cleveland, in the county of Cuyahoga and branch D is included an electro-magnet F, State of Ohio, have invented certain new and the armature G of which is retracted by a 5 useful Improvements in Automatic Cut-Outs spring H, the tension of which is adjusted by for the Shunt-Coils of Compoundound Conthe set-screw (Z or other suitable device. stant Current Dynamo Electric Machines; I is an insulated block or stop, against which and I do hereby declare the following to be rests the upper and free end of the armature a full, clear, and exact description of the in- G when retracted by its spring. 6 [0 vention, such as will enable others skilled in K is an adjustable contact, with which the the art to which it appertains to make and armature engages when drawn forward by use the same. the electro-magnet. To the pivotal end L of My invention relates to an improved autothe armature is electrically connected a conmatic cut-out for the shunt-coils of compounddnctor L, the opposite end of which is elec- 6 wound constant-current dynamo-electric matrically connected with the binding-post a. chines. One end N of the shunt-coilof the dynamo is The object of the invention is to provide a electrically connected with the contact K by device which will automatically open-circuit being attached to the standard M or in any the shunt-coils of a compound-wound dynamo other desired manner. 20 on the breaking of the external or working The operation of the improvement is briefly circuit, whereby when the external circuit isas follows: hen the dynamo is generating closed through a human body, as by taking the normal current, the pull of the electrohold of the broken ends in the attempt of remagnet F will be sufficient to retain the armapairing, a greatly-diminished current will be ture G in contact with the contact K, and thus 25 generated and all danger to workmen will maintain a closed circuit from binding-post (1, thus be avoided. through conductor L, armature G, contact K, Vith this end in view the invention constand M, and conductor N, to the shunt-coils sists in the combination, with the shunt-coils on the field-magnets, and thereby cause the of a compound-wound dynamo-electric mashunt-coils of the machine to be energized by 3o chine, of a circuit-controlling device for m ainthe current diverted thereto. Should a break taining the shunt-coil circuit of the dynamo occur in the main or external circuit, or the closed while the machine is generating its circuit be opened for any cause, magnet F normal supply of current, and for antoinatiwill be instantly weakened to such an extent cally opening said circuit on the breaking of by the drop in the current as to allow the 3 5 the external circuit, and thereby reducing the spring H to retract the armature against the current generated by the machine. insulated stop I, and thus break the circuit The invention further consists in certain conveying current to the shunt-coils of the features of construction and combinations of machine. The electro -motive force of the parts, as will hereinafter be described, and machine then becomes exceedingly small and 4o pointed out in the claims. continues so until a very low-resistance path The drawing is a diagram illustrating the is made for the current on the external cirinvention. cuit, which will allow the series coils of the In the accompanying drawing, illustrating machine to build up the current to its normal one embodiment of my invention, A represtrength, when the clectro-magnet will be 5 45' sents a compound-wound dynamo having lowsufficiently energized to close the circuit of resistance field-coils B coupled in series with the sh uni-coils and again bring the latter into the armature and line and high-resistance action.

shunt-coils C, the ends of the latter being con- By the employment of my improvement nected to the terminal contacts or bindingwith dynamos constructed to generate high- I00 50 posts a b of the machine. tension currents the danger to life and prop- D E represent the two wires or branches erty resulting from breakage or opening of the external circuit is practically obviated, as the current generated by the machine will on the breaking or opening of the external circuit be automatically and instantly reduced to such an extent as to be harmless.

It is evident that many changes in the construction and relative arrangement of parts might be resorted to Without departing from my invention, and hence I would have it understood that I do not restrict myself to the construction and arrangement of devices and circuits herein shown and described; but,

Having fully described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. The combination, with a compoundwound dynamo-electric machine, of a cut-out electro-magnet in the external or working circuit and a circuit making and breaking device in the shunt-circuit of the dynamo controlled by the electro-magnet, substantially as described.

2. The combination, with a compoundwound dynamo-electric machine, of a cut-out electro-magnet in the external or working circuit, constructed to act in response to a current of normal strength in the main circuit, and a circuit making and breaking device in the shunt-circuit of the dynamo controlled by the electro-magnet, whereby the shunt coils of the dynamo are automatically opencircuited on the opening or breaking of the Working circuit and are again automatically closed when the current in the external circuit has regained its normal strength, substantially as described.

3. The combination, with the shunt-coils of a compound-Wound dynamo-electric machine, of a circuit making and breaking device included in the circuit of the shunt-coils, an electro-magnet included in the external or series circuit of the machine, constructed to actuate the circuit making and breaking device in response to a current of normal strength in the external circuit to close the shunt-circuit, and means for automatically opening the shunt-circuit when the current through the magnet falls below a predetermined point, substantially as described.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

SIDNEY ll. SHORT.

Witnesses:

J. 0. WILLIAM, E. II. MORRISON. 

